Nail deformity includes “rolled nail” and “ingrown nail.” Frequently, the word of the rolled nail and the word of the ingrown nail are used without being distinguished from each other. However, in general, a state as if the nail is rolled laterally is called as “rolled nail,” and a state that the nail is significantly curved and both ends of the nail are growing into skin or flesh (soft tissue) is called as “ingrown nail” in many cases. In case of the ingrown nail, one or both sides of lateral edges of the nail are deeply growing into a nail groove along with the growth of the nail, and stuck in the soft tissue (flesh inside the nail) causing inflammation accompanying pain or severe pain. The ingrown nail is mainly caused by pressure, wound, overcut and birth defect, for example. The ingrown nail frequently occurs especially on a big toe. As the conventionally known method for curing the ingrown nail, a method of removing the lateral edge of the nail ingrown in the nail groove by a surgical operation, a method of using a corrector or a correcting device, and a method of using a treatment agent for the correction are known, for example. As the method of using the corrector and the correcting device, for example, U.S. Pat. No. 4,057,055 (Patent Document 1), Japanese Unexamined Patent Application Publication No. H08-215227 (Patent Document 2), Japanese Unexamined Patent Application Publication No. 2001-276104 (Patent Document 3), Japanese Unexamined Patent Application Publication No. 2011-104231 (Patent Document 4) and Japanese Unexamined Patent Application Publication No. 2002-360619 (Patent Document 5) can be seen. As the method of using the treatment agent for the correction, Japanese Unexamined Patent Application Publication No. 2004-238288 (Patent Document 6) can be seen. Furthermore, as a device preferably used for the process of using the treatment agent for the correction, the device described in WO2008-142880 (Patent Document 7) is known.
However, the method of using the surgical operation is complicated and the width of the nail plate becomes narrow permanently after the operation. Furthermore, in the method of using the surgical operation, the nail growing into the soft tissue is partly cut and removed. Thus, the operation is difficult when there is a risk of bacterial infection. Even if the ingrown nail is temporarily cured by the surgical operation by partly removing the nail, tendency of curling in a curling direction is not corrected as whole the nail. Thus, the ingrown nail often occurs again after the operation. Consequently, it is now generally thought that a method not using the surgical operation, i.e. a conservative method, is preferable as the method for curing the ingrown nail.
The method of using the corrector or the correcting devise will be described below. For example, Patent Document 1 proposes a devise that includes post members adhered to both lateral edges of an outer surface of a nail having the ingrown part along the longitudinal direction of a finger having the nail, and a tension member such as a rubber string, wherein the post members have a vertical part to hold the tension member, and the post members adhered to the both lateral edges of the outer surface of the nail are pulled toward each other by the tension member to lift up the both lateral edges of the nail. In Patent Document 2, a method of curing the rolled nail is proposed by adhering a plate-like piece made of shape memory alloy or shape memory resin on a curved surface of the rolled nail using an adhesive agent and then raising the environmental temperature to a predetermined temperature or more to use a restoring force of the plate-like piece. In Patent Document 3, a corrector for correcting deformation of the nail and a correcting method using the corrector are proposed as explained below. The corrector for correcting deformation of the nail described in Patent Document 3 is formed to hook a hook portion of a wire or the like on the ingrown part of both lateral edges of the nail so as to pull the both lateral edges of the ingrown nail toward the center direction. More specifically, the corrector includes a first engagement portion to be engaged with one lateral edge in the width direction of a nail body, a first correcting body having a first contact portion to be in contact with a part of the surface of the nail body and a first connecting hook portion to be connected with the first contact portion, a second engagement portion to be engaged with the other lateral edge in the width direction of the nail body, a second correcting body having a second contact portion to be in contact with a part of the surface of the nail body and a second connecting hook portion to be connected with the second contact portion, and a correcting operation portion that is engaged with the first connecting hook portion and the second connecting hook portion to hold the first connecting hook portion and the second connecting hook portion in a state of being pulled toward the center portion side in the width direction of the nail body by a predetermined hanging force so that the one lateral edge and the other lateral edge of the nail body are hanged up. Patent Document 4 discloses an orthosis for the rolled nail formed by a triangle-shaped plate having a U-shaped groove on one side of the triangle and a metal hooking fitting on an apex opposed to the groove, and a hook formed in S-shape so that an axis of the hook is rotated 90° between both ends.
In the device described in Patent Document 1, however, a force applied to the both lateral edges of the ingrown nail is larger in the direction of pulling the nail toward the center direction than the upper direction which is required for extracting the ingrown part from the nail groove. Thus, it is difficult to obtain an appropriate effect of the correction. In addition, several months are required for a treatment when using this devise. However, the post member of the device described in Patent Document 1 has a vertical part, and therefore it is very difficult to live a daily life while the device is attached. Consequently, the device described in Patent Document 1 is not practical. Furthermore, in the nail deformity such as the ingrown nail, the nail is deeply growing into the skin/flesh of the nail groove even at a place near the root. In addition, the nail is covered by a posterior nail fold and cannot be seen. Consequently, the nail is growing into the nail groove at the root of the nail and the curvature of the lateral portion of the nail covered by the posterior nail fold should be corrected in order to obtain a sufficient effect of the correction and prevent the ingrown nail from occurring again. Since this devise basically acts only on the center part of the exposed nail, significant correcting effect cannot be expected. In particular, as a problem, this devise is not suitable for correcting the serious ingrown nail where the lateral edges of the nail is deeply growing into the skin/flesh and the ingrown nail occurs again as the nail grows long.
In the method described in Patent Document 2, since the plate-like piece made of shape memory alloy or shape memory resin is adhered on the nail surface by the adhesive agent, the nail surface cannot follow the plate-like piece when the plate-like piece is flattened. As a result, when adhesive strength of the adhesive agent is low, the plate-like piece is easily peeled off from the nail surface. On the contrary, when the adhesive strength is too high, restoring force of the plate-like piece is obstructed or other inconveniences may occur. Furthermore, the above described plate-like piece acts only on the center part of the exposed nail. Thus, there is the same problem as Patent Document 1.
In the method described in Patent Document 3, same as the case of using the above described plate-like piece, several months are required for a treatment. Also, since the patient should live a daily life while the corrector is attached, this method is very painful for the patient. In addition, in this method, since the hook of the wire is hooked on the lateral edges of the ingrown nail, pain and bleeding are often accompanied. For the patient, the problem is not only in pain. As another problem, this method cannot be applied to the patient when the nail is hard or brittle and cannot be applied to the patient of tinea unguium. Furthermore, since the ingrown part is lifted up by the hook having a thin wire-shaped hook, the force is necessarily applied to only a part of the lateral edges of the nail. Thus, it is difficult to evenly and efficiently correct the curvature of the lateral edges of the nail. In addition, as explained above, in the nail deformity such as the ingrown nail, the root part deeply growing into the skin/flesh of the nail groove cannot be seen in many cases. Thus, it is very difficult to hook the hook of the wire on the above described part without imparting burdens to the patient. Consequently, as a problem, the curvature of the root part of the nail cannot be solved eventually and the deformation of the nail occurs again.
The triangle-shaped orthosis disclosed in Patent Document 4 aims for efficient correction in a state that the nail edge is engaged with the wide U-shaped groove formed on one side of the triangle. However, the U-shaped groove is too long and has a constant cross-sectional shape over the entire length. In case of the serious ingrown nail or when the edge part of the nail is deformed into a nonlinear shape, in particular, the orthosis is difficult to be attached. Thus, practicality is low. In addition, because of the shape of the orthosis, it is difficult to attach the orthosis on the root of the nail without imparting burdens to the patient. Thus, there is the same problem as the above described Patent Document 1 and the like.
Patent Document 5 discloses a corrector of ingrown nail having an operation portion to be held in a hand by an operator, a contact portion to be in contact with the nail, and a tip groove having an approximately J-shape in a cross-section provided on the contact portion so as to be inserted into the ingrown part of the nail, wherein the operator corrects the curved state of the ingrown nail by moving the corrector in a state that the tip groove is inserted into the ingrown part of the nail, the corrector and the nail are adhered with each other in the corrected state, the corrector is shaped to fit the shape of the nail so as to be integrated with the nail in appearance, and then an unnecessary part is removed as the nail grows long. Furthermore, in Non-Patent Document 1, an example of the treatment using a tool (splint) based on substantially same technical concept with Patent Document 5 is reported. In the corrector shown in the figures of Patent Document 5, it seems at a glance that the corrector is designed to be inserted to the root of the nail. However, in practice, as explained above, Patent Document 5 only discloses that only “tip groove” of the corrector is attached to the tip portion of the nail. For example, in the example shown in FIG. 1 of Patent Document 5, the width of the tip groove to be inserted into a reverse side of the nail is disclosed as 3 mm. Of course, the tip groove having the width of 3 mm cannot be assumed to be inserted into the root of the nail. In actual, as described above, Patent Document 5 only discloses that “tip groove” is inserted. In the figures, a state that only the tip portion is inserted is shown. Note that the above described width of 3 mm is considered to be the minimum width required for securing a size and strength when considering the technical concept of Patent Document 5, i.e., the nail is corrected by twisting the nail in a state that the end portion of the nail is held by the tip groove.
If the corrector has the above described shape as disclosed in Patent Document 5, heavy burdens are placed on the patient when the corrector is tried to be inserted to the root of the nail. In the embodiment shown by the picture in Non-Patent Document 1, actually, only an extremely short area of the tip is inserted between the lateral nail edge and the lateral nail fold, i.e., a portion that the nail is growing into the skin. As a result, the effect of the correction is applied only to the tip of the nail and surrounding area. Accordingly, an effect of the corrector of Patent Document 5 is weak for correcting the serious ingrown nail. In addition, the root of the nail is not sufficiently corrected and the ingrown nail occurs again as the nail grows. In addition, same as the case of Patent Document 4, the tip groove of the corrector of Patent Document 5 has a constant cross-sectional shape over the entire length. Accordingly, when the lateral edge of the nail is deformed in an irregular shape, for example, it is sometimes difficult to insert the corrector to the root of the nail by force.
The method of using treatment agent for the correction described in Patent Document 6 will be described below. Patent Document 6 discloses a treatment agent for a deformed nail such as an ingrown nail including one kind of a reducing agent selected from a group consisting of cysteine, thioglycolic acid and thioglycolic acid salt, and discloses a correcting method using the treatment agent. In the invention of Patent Document 6, focusing on the fact that the composition of the nail is similar to the composition of the hair, permanent waving technique for the hair is applied to the correction of the nail. More specifically, the following operations are performed. An emulsifier is added to the above described reducing agent, which is a main component of the first agent for the permanent waving, to obtain a cream-type medicine containing 5 wt. % of the reducing agent. Thus, the obtained agent is used as the treatment agent for the deformed nail. First, the nail (deformed nail such as an ingrown nail) is grown long enough and two or three small through holes are formed on the grown part (free edge) located at the tip of the nail. Then, the above described treatment agent is applied to the whole external surface of the nail and left to stand for approximately 30 minutes to reduce and cut disulfide bond of the cysteine contained in a keratin protein in the nail forming two mercapto groups. Thus, the nail is softened. The treatment agent is washed and removed by warm water. After the nail is softened as described above, the shape of the nail is corrected by the operator, an ordinary temperature-curable resin is applied to the external surface of the nail to fix the nail so that the small through holes formed at the free edge of the nail, left to stand for approximately 1 hour, and then the resin for fixing the nail is removed. However, the operator corrects the nail by fingers in this method. Accordingly, the operation is complicated and requires skilled hand. In addition, the nail should be grown long enough to fix the nail after the correction. However, many patients of the ingrown nail overcut the nail. Thus, as a problem, the correction operation cannot be performed immediately in many cases. Furthermore, the root of the nail is basically not corrected. Thus, there is the same problem as Patent Document 5 and the like.
Patent Document 7 discloses a devise for correcting the ingrown nail by lifting up a nail edge portion ingrown in the nail groove including: a vertical push-down member provided with a push-down head at a lower end of the push-down member; a lift-up angle maintaining means extended in a horizontal direction, the push-down member is attached to an intermediate part of the lift-up angle maintaining means; and a pair of lift-up members extended below from two positions of the lift-up angle maintaining means, the two positions are opposite to each other with respect to the intermediate part to which the push-down member attached, anchors are held on the lower end of the lift-up members, wherein a tension is applied to the lift-up members of the device attached to the external surface of the nail, the lift-up force to correct the ingrown nail is applied to the anchors attached to both lateral portions of the external surface of the nail, and the intermediate portion of the external part of the nail is pushed toward the thickness direction of the finger by the push-down head of the push-down member. In particular, if the above described correcting device is used together with the nail softener described in Patent Document 6, for example, the ingrown nail can be surely corrected without giving pain to the patient by a simple operation within a short time of approximately 30 minutes to 1 hour. However, there is a need to take necessary steps to maintain the shape of the nail after the correction treatment and prevent the ingrown nail from occurring again. Actually, there is no suitable means for achieving this purpose.